Granny flats in Perth,
built to rent.
The Property Plug is a Perth building broker with 8 granny flat designs from $217,500 to build before siteworks. In WA an ancillary dwelling up to 70m2 can be rented to a private tenant, so a granny flat adds a second income to a block you already own or are buying, at no cost to you.
Last updated June 2026. Prices are indicative and exclude land. Yield figures on this page are illustrative general information, not financial or credit advice.
A granny flat in WA is an ancillary dwelling. Under the Residential Design Codes it can be up to 70m2 of floor area, or 80m2 if designed for accessibility, and since 2020 it can be rented to anyone, not only family. That is the rule that makes a granny flat a real dual income build.
For years a WA granny flat could only house a family member. That changed in 2020, when the State Government allowed ancillary dwellings to be let to a private tenant. More recent R-Codes changes removed the old minimum 350m2 lot size and now allow ancillary dwellings on grouped, multiple-dwelling and strata lots, not just single-house blocks. The practical effect is simple. If your design stays within 70m2 and meets the deemed-to-comply setbacks for your suburb, you generally do not need planning approval, though you always need a building permit.
That is why every design below is drawn to sit within or close to 70m2. It keeps your approval path clean and keeps the whole footprint rentable. We confirm the exact deemed-to-comply requirements for your local government area before you commit, because setbacks, open space and parking can vary council to council.
Rule confidence: high. The 70m2 limit, the 80m2 accessibility allowance and the rent-to-anyone change are set out in the WA Planning Commission ancillary dwelling guidance and the R-Codes. Always verify the deemed-to-comply detail for your specific lot and council before contracting.
| Maximum floor area | 70m2 (80m2 if accessible) |
|---|---|
| Rent to a private tenant | Allowed since 2020 |
| Minimum lot size | No minimum (350m2 rule removed) |
| Planning approval | Often not needed if deemed-to-comply |
| Building permit | Always required |
| Eligible lots | Single, grouped, multiple and strata |
As an illustration, a Haven granny flat in Baldivis costs $238,268 for the home plus Baldivis's real siteworks of $20,768, land excluded. Let at $450 a week, that is $23,400 a year and a gross yield of about 9.8% on the build cost. Illustrative only, not advice.
| Line | Figure | Note |
|---|---|---|
| Haven design (68m2) | $217,500 | Base build price, fixed-price contract |
| Baldivis siteworks | $20,768 | Real per suburb figure from our data |
| Home plus siteworks | $238,268 | Land purchased separately |
| Indicative rent | $450/week | Representative for a small corridor dwelling |
| Annual rent | $23,400 | 52 weeks, before vacancy and costs |
| Gross yield on build cost | 9.8% | Illustrative, excludes land and holding costs |
This worked example is general information only and is not a forecast, a valuation, or financial or credit advice. The gross yield is calculated on the build cost alone. It does not include the cost of land, stamp duty, holding costs, vacancy, management fees, rates, insurance or maintenance, all of which lower a real return. Actual rent depends on the suburb, the finish and the market at the time you let. Confirm rent expectations with a local property manager and your own numbers with a qualified adviser before you commit.
IndicativeEstimate only, not a quote or an offer. Figures combine a home design starting price with the suburb siteworks and do not include land. Designs, builders, land and pricing change and are subject to availability. We confirm a fixed price with your matched builder on enquiry.
The point of the example is the shape, not the exact percentage. A granny flat is a small, low-land-share build, so the rent sits against a modest construction cost. That is structurally why a well-placed ancillary dwelling can lift the blended yield on a block well above a single home on the same land. To run your own version, start from a design base price, add your suburb siteworks, then divide the rent your property manager quotes by that total. Our rental yield guide walks through the maths in full.
Each design is priced from its base build cost. Most sit within the 70m2 rentable limit, with two larger dual-occupancy options for blocks that suit a bigger second dwelling. The builder is matched and revealed when you request private access.
Designs over 70m2 (for example Cosy Corner and Sunset and Bayview and Synergy) exceed the standard rentable ancillary limit and suit dual-occupancy or accessible builds. We confirm what is rentable on your specific lot.
Dual income means a single lot earning two rents, or one rent plus your own home. A granny flat is the simplest dual income build in Perth because the WA 70m2 ancillary rule lets you rent the second dwelling to anyone, lifting the return on land you already control.
There are three common ways Perth owners use a granny flat for income.
- Rent both. Buy or hold a block, build a main home and a granny flat, and let each separately. Two leases on one title spread your vacancy risk and lift the blended yield.
- Live in one, rent the other. Owner-occupy the main home and let the granny flat. The rent offsets your mortgage while you keep one set of rates and one block.
- Add to an existing home. Already own in a Perth corridor? Add an ancillary dwelling to the backyard and turn idle land into a second income, subject to your lot meeting the deemed-to-comply rules.
For investors the appeal is the land share. A granny flat carries very little extra land cost because it sits on a block you already have, so almost all of your spend is the depreciable building. That is the engine behind the granny flat investment case and the dual income comparison.
- Granny flat investmentDepreciation, the dual income thesis and the full numbers.
- Granny flat cost in PerthBuild price bands, siteworks and what all-in really means.
- Rental yieldHow granny flat yield is calculated, step by step.
- Dual income propertiesOne block, two rents, versus a single home.
- WA ancillary dwelling rulesThe 70m2 rule, setbacks and permits in detail.
- House and land in PerthPair a granny flat with a new home on the same block.
Independent and on your side. We are paid by the builder, never by you.
Can you rent out a granny flat in WA?
Yes. Since the 2020 R-Codes change a Western Australian ancillary dwelling can be rented to a private tenant, not just a family member, and no special permission is needed to list it. That is the rule that turns a granny flat into a genuine dual income asset.
How big can a granny flat be in WA?
A WA ancillary dwelling can be up to 70m2 of floor area under the R-Codes deemed-to-comply pathway, or up to 80m2 where it is designed for accessibility. Stay within those limits and the dominant suburb setbacks and you generally avoid planning approval, though a building permit is still required.
What yield does a granny flat return in Perth?
As an illustration only, a Haven granny flat built in Baldivis at $238,268 home plus siteworks, let at $450 a week, shows a gross yield of about 9.8% on the build cost. This excludes land, holding costs and vacancies and is general information, not a forecast or advice.
How much does a granny flat cost to build in Perth?
Granny flat builds on The Property Plug panel start from $217,500 for the design. Add real per suburb siteworks, for example $20,768 in Baldivis, for a home plus siteworks figure from $238,268. Land is separate. See the granny flat cost guide for the full breakdown.
How long does a granny flat take to build?
Allow around 8 months from contract to handover for a granny flat through our panel, after design, approvals and siteworks. Smaller footprint than a full home, but the same fixed-price contract and inclusions discipline.
Download the granny flat price list
All 8 designs, full inclusions and real from-prices, with your matched builder. One request matches it. Free to you, we are paid by the builder.